1309 Hyperborea, provisional designation 1931 TO, is a carbonaceous background asteroid from the outermost regions of the asteroid belt, approximately 57 kilometers in diameter. It was discovered on 11 October 1931, by Soviet astronomer Grigory Neujmin at the Simeiz Observatory on the Crimean peninsula.[16] The asteroid was named after Hyperborea, the northern homeland of a Greek mythical race of giants.[2]

This minor planet was named after Hyperborea, the homeland of the Hyperboreans, a Greek mythical race of giants associated with the cult of Apollo. Herodotus placed the region far to the north of Thrace beyond the North Wind. It was therefore believed to be a region of perpetual sunshine. Lutz Schmadel, the author of the Dictionary of Minor Planets, learned about the naming from Russian astronomer Nataliya Sergeevna Samoilova-Yakhontova (see 1653 Yakhontovia).[2]